@jogan it could also be the last part of what afakeman said "i have no bounty on my head."perhaps the game flagged him as hostile against the town but because he did the killing sneaky the bounty system didn't trigger?well its absurd if i'm right...but could be?try kill some more guards and stuff reload and stuff...just...remember if your werewolf or vampire or vampire LORD for that sake you should look for johon's anser

@jogan it could also be the last part of what afakeman said "i have no bounty on my head."perhaps the game flagged him as hostile against the town but because he did the killing sneaky the bounty system didn't trigger?well its absurd if i'm right...but could be?try kill some more guards and stuff reload and stuff...just...remember if your werewolf or vampire or vampire LORD for that sake you should look for johon's anser

The npcs do not attack the player when he or she is a vampire in the Dawnguard DLC unless he/she transforms into vampire lord or simply attacks people.